Electron discharge device



I M. ARON ETAL 2,840,736 ELECTRON DISCHARGE DEVICE Jun 24, 1958 FiledOct. 17. 1955 I 34 v Q L5.

Fig. 2.

WITNESSES 23 24 INVENTORS 26 Mitchell Aron a Mi Carl F. Miller. BY

ATTORNEY United States Patent ELECTRON DISCHARGE DEVICE Mitchell Aron,Newark, N. J., and Carl F. Miller, Bath, N. Y., assignors toWestinghouse Electric Corporation, East Pittsburgh, Pa., a corporationof Pennsylvania Application October 17, 1955, Serial No. 540,777

4 Claims. (Cl. 313-6) This invention relates to electron dischargedevices and, more particularly to improvements in electrode assemblies.

it is an object of our invention to provide an improved electrodeassembly structure for an electron discharge device.

It is another object to provide an electron discharge device which isrugged and able to operate under conditions of shock or vibrations.

, -It is another object to provide an electrode assembly particularlysuited to those devices requiring high value of transconductance.

It is another object to provide an electrode structure adaptable tointernal shielding of twin-type tube structures.

It is another object to provide an electrode structure that is suitablefor mechanical or automatic assembly. I

These and other objects are effected by our invention as will beapparent from the following description taken in accordance with theaccompanying drawing throughout which like reference characters indicatelike parts, and in which:

Figure l is a top view of an electrode assembly embodying our invention;

Fig. 2 is a side view partly broken away of the electrode structureshownin Fig. 1; and

Fig. 3 is a perspective view of the mount support structure shown inFig. 1.

Referring in detail to the drawing, there is shown an electrodedischarge device embodying our invention. The device shown for purposesof illustrating our invention is a twin triode but the teachings may beutilized for any number of electrode structures such as for a twintriode, twin pentode, or a triode-pentode.

The electrode discharge devices include an envelope 10 closed at thelower end with a button stem header 12 closed at the upper end by anexhaust tubulation 14. The electrode structure 13 embodying ourinvention may be incorporated in any suitable type envelope structureand the one shown here is only for the purposes of illustration. Aplurality of lead-in conductors 16, 18, 20, 22, 24, 26, 28, 30 and 32are sealed through the header 12 and are welded directly to theirrespective elements of the electrode assembly 13 within the envelope 10.The lead-in conductors not only supply the necessary voltage to theelements of the electrode assembly 13 but also sup port the electrodestructure 13 within the envelope 10.

The electrode assembly 13 is comprised essentially of twoidenticaltriode electrode structures '15 positioned back to back andseparated from each other by means of a'planar shielding member 34. 'Inthe specific embodimerit shown, the two separate 'triode structures farepositioned so that their planar elements are substantially parallel tothe header 12 of the envelope 10.

For ease in describing the structure, the description is limited to theupper triode structure 15. The upper electrode structure 15 is comprisedof a support wafer 36 of any suitable material such as ceramic providedwith grooves or channels 38 and 40 in the upper surface. The

2,840,736 Patented June 24, 1958 grooves may be machined or molded in asuitable manner. In the specific embodiment shown, one channel 38 is cutto a depth of approximately of the thickness of the wafer 36 andprovides a channel or slot for positioning a cathode 42 within theceramic wafer 36. The bottom surface of the channel is substantiallyparallel to the wafer surface while the side walls are substantiallyperpendicular. It is desirable to provide integral ridge portions 44 onthe bottom surface of the channel to aid in thermal isolation of thecathode 42 from the main wafer 36. The cathode 42 utilized in thespecific embodiment comprises a tubular metallic sleeve 46 having arectangular cross-section. An electron emissive coating 48 is applied ina suitable manner on the outer surface of one of the large dimensionedsides of the rectangular sleeve while the other surface rests on theridge portions 44 on the bottom of the channel 38. A tab 59 is providedon the cathode sleeve 46 to which the lead-in 18 is welded in a suitablemanner. A heating element of filament 52 is positioned within thetubular sleeve 46 of the cathode 42 and is electrically insulatedtherefrom to provide heat .to the emissive coating 48 of the cathode 42.The ends of the filament 52 are connected to lead-in wires 20 and 22.

The second groove or channel 46 is also located in the same surface ofthe wafer 36 but at a lesser depth than the cathode channel 38. Thechannel 40 is positioned at an angle with respect to the cathode channel38 and in the specific embodiment shown is at right angles with respectthereto. The bottom of channel 40 is also substantially parallel to theface of the wafer 36 while the side walls are substantiallyperpendicular. The channel 40 provides means for positioning a controlgrid 60 within the electrode structure 15. This control grid 60 is inthe form of a frame grid member and of a planar type structure. The grid60 essentially consists of a frame 62 of sheet-like material and in thespecific embodiment substantially quadratic which supports and positionsthe active portion 64 of the grid 60. The active portion 64 of the grid69 consists of lateral wires or a mesh structure across an aperture inthe rectangular frame member 62. The lateral wires may be attached tothe frame 62 by any suitable means such as notching and peening, weldingor brazing. The dimensions of the frame grid 60 are such that onedimension is such as to rest within the grid channel substantiallyagainst the sides of the channel 40 while the other dimensions of theplanar grid 60 is such that the active portion 64 extends at leastacross the width of the cathode channel 38. The depth of the gridchannel 40 with respect to the cathode channel 38 is carefullycontrolled to obtain the proper spacing between the cathode 42 and thegrid electrode 60. The grid electrode 60 is provided with a tab 66 onone side of the rectangular frame and is attached to the stem lead 24.The other side of the frame grid 60 resting within the grid channel 40is secured to the ceramic wafer 36 by means o f a ceramic or insulatingwasher 67 located about the stem lead 26 and held in place by an'eyelet68. It may also be desirable to further insure proper spacing betweenthe cathode 42 and grid 60 to provide ceramic projections which must becarefully controlled as to their height on the underside of the gridframe 62 adjacent tothe cathode 42. These projections touch the cathode42 and when the grid 60, is secured down by means of the insulatingwasher 66the projections will press down on the cathode 42 and retainthe cathode 42 in a fixed or locked position within the cathode channel38.

A plate member 70 is next provided or positioned within the electrodestructure 15 and consists essentially of a metallic elongated member ofsuitable material having a U-shaped cross-section. Raised portions orribs 72 are provided on the exterior surface near the top of the legs 74of the plate 70. Matching depressed portions 76 are provided in the sidewalls of the cathode channel 38 near the top to retain the plate 70 inthe wafer 15. The plate 70 is thus locked into the wafer in a mannershown in Fig. 2. Out-turned portions or tabs 78 are provided on the endsof the legs 74 at each corner to rest on the top surface of the ceramicwafer 15. One of the tabs 78 is made longer to provide a means ofwelding the stern lead 28 to the plate 70.

Referring to the entire electrode assembly 13, the specific embodimentutilizes integral stems and lead-ins 16, 18, 20, 22, 24, 25, 28, 3t) and32 so that it is necessary that the lower electrode structure 15 beassembled first and positioned with the channel surface downward overthe lead-ins. The shielding member 34 is positioned on top of the lowerelectrode 15 and then the upper electrode structure 15 is positioned andattached to the lead-ins to complete the electrode assembly 13. It isalso possible that the same lead-in might be made in two separate partswhich would permit fully assembling the upper and lower electrodestructures 15 into the electrode assembly 13 prior to insertion into theenvelope and then welding the lead-ins to the corresponding lead-ins orsupports in the stem.

The metal shield 34 provided between the two electrode structures isprovided with various holes punched therein to provide clearance withrespect to the stem leads passing through the structure. A stern lead-in32 is also provided for the shield 34 and is welded to the metal shield34 and may be grounded on the exterior of the envelope 10. The shieldserves as an electrostatic shield between the upper and lower electrodestructures 15. The shielding effect of the metal shield 34 may beenhanced by extending the shield 34 beyond the two electrode structures15 to substantially the tube wall of the envelope 10.

In the manufacture of the device where two separate stem leads are used,the lower electrode structure 15 could be assembled by positioning ordropping the cathode sleeve 46 with coating 48 and heater into thecathode groove 38. The upper block 36 is held in a position with thechannels upward. The next operation would be the positioning or droppingof the control grid 60 within the grid channel 40. The next step wouldbe the press in or snap in positioning of the anode member 70 within thecathode channel 38. The upper portions of the stem leads could then beinserted or prior to the above assembly, and welded and secured in amanner previously described to electrodes. It should be noted that thestem lead 26 provides electrical connection to the grid of the lowerelectrode structure 15 and this grid is mechanically secured by stemlead 24 on the other side. The metal shielding member 34 is theninserted over the lead-in members after the lower electrode structure 15is inverted so as to rest on the back of the wafer of the lowerelectrode structure and is welded to the lead-in member 32. The upperelectrode support or wafer 36 is then mounted over the lead-in membersso that its back portion rests against the metallic insulating member 34and the remaining elements of the upper electrode structure arepositioned within the wafer 36 in a similar manner as that describedwith respect to the lower electrode structure 15. The upper lead-inportion could then be welded to the lower support stem lead-in portion.Clamping members (not shown) may be used around portions of theperiphery of the wafers 36 to retain them together. This structure lendsitself to automatic assembly of elements into the ceramic wafers.

While we have shown our invention in only one form,

4 it will beobvious to those skilled in the art that it is not solimited but is susceptible to various other changes and modificationswithout departing from the spirit and scope thereof.

a We claim as our invention:

1. An electron discharge device comprising an envelope having anelectrode assembly within said envelope, said electrode assemblycomprising a plurality of planar type electrodes, means for positioningsaid electrodes within said assembly comprising a wafer having at leasttwo grooves of different depths intersecting at an angle in one surfacethereof, an electrode positioned within the lower portion of the deepestof said grooves, and another electrode within the other of said groovesto support and space said electrodes in a fixed relationship withrespect to each other.

2. An electron discharge device comprising an envelope having anelectrode assembly within said envelope, said electrode assemblycomprised of a plurality of planar type electrodes consisting of atleast a cathode, grid and anode, means for positioning said electrodeswithin said assembly comprising a wafer of insulating material, saidwafer having at least two grooves of different depths intersecting at anangle in one surface thereof, said cathode positioned within the lowerportion of the deepest of said grooves, said anode positioned in theupper portion of said deepest groove and said grid electrode positionedin the lower portion of another of said grooves intermediate saidcathode and anode to support and space the electrodes in a fixedrelationship with respect to each other.

3. An electron discharge device comprising an envelope having anelectrode assembly within said envelope, said electrode assemblycomprised of a plurality of planar type electrodes consisting of atleast a cathode, grid and anode, means for positioning said electrodeswithin said assembly comprising at least one water of insulatingmaterial, said wafer having at least two intersecting grooves ofdifferent depths in one surface thereof, said cathode positioned withinthe lower portion of the deepest of said grooves, said anode positionedin the upper portion of said deepest groove and said grid electrodepositioned intermediate said cathode and said anode within another ofsaid grooves.

4. An electron discharge device comprising an envelope and havingtherein a unitary electrode assembly comprised of a first and a secondtube structure, said first tube structure comprised of a plurality ofelectrodes and an insulating support having a surface provided with aplurality of intersecting channels, said electrodes received within saidchannels to support and space said electrodes in a fixed relationshipwith respect to each other, said second tube structure comprised of aplurality of electrodes and an insulating support having a surfaceprovided with a plurality of intersecting channels, said electrodesreceived within said channels to support and space said electrodes in afixed relationship with respect to each other, means for maintainingsaid first and second tube structure so that said insulating supportmembers are positioned back to back, and metal shielding meanspositioned intermediate said first and second tube structures.

References Cited in the file of this patent UNITED sTA Es PATENTS2,310,811 Schantl et al. Feb. 9, 1943 2,343,849 Binneweg Mar. 7, 19442,663,818 Walsh Dec. 22, 1953

